Foam thermoplastic resins are finding increased utility in either extruded or injection molded plastic articles. Such foam resins provide articles having both strength and light weight.
Applicant's copending application U.S. Ser. No. 598,801 filed Apr. 10, 1984, now U.S. Pat. No. 4,544,677, teaches that known particulate impact modifiers may be used as nucleating agents in thermoplastic foams. However, the data contained therein also supports the fact that, in general, known impact modifiers for thermoplastic resins fail to have an appreciable impact modifying effect on thermoplastic foam.
It has now been discovered that certain foam thermoplastic resins can be impact modified at low temperature by use of polysiloxane-polycarbonate block copolymer resin as an impact modifier. The use of such impact modifier enables the production of foam thermoplastic articles with exceptional impact strength at low temperature.